Sealing strip for refrigerator door



Dec. 18, 1956 c. H. BEARE SEALING STRIP FOR REFRIGERATOR DOOR OriginalFiled Feb. 6, 1951 INVENTOR. 6/4/1121. E5 HBEA RE ATTORNEYS UniteSEALING STRIP F GR REFRIGERATOR DOGR Charles H. Beare, Dayton, Ohio,assignor to General Motors Corporation, Detroit, Mich, a corporation ofDelaware 3 Claims. on. 20-69) This invention relates to a cushioningsealing strip of rubber or rubber-like material especially adapted foruse as a sealing strip for refrigerator doors and the like, and is adivision of copending application S. N. 209,624, now Patent 2,716,778,patented September 6, 1955, assigned to the assignee of the presentinvention.

Sealing strips for this purpose made of sponge rubber material are wellknown, but such strips are subject to the defects of absorbing moisture,tending to stick to the door or door jamb surfaces against which theyare compressed when the door is closed, and being relatively Weak instructure and easily torn or otherwise damaged.

Also sealing strips made of soft rubber material having a compressiblehollow air-filled bulb or channel are well known. Such hollow rubberchannels must be made with a substantial wall thickness to provide thenecessary strength and resistance to compression when first installed.Also such strips after a period of use are subject to the defect ofcracking or failure of the relatively thick rubber walls at thelongitudinal lines thereof where the partial collapse or bending of thecross section thereof is concentrated when the strip is repeatedlycompressed in use. Such concentration of bending of said walls resultsfrom the necessary substantial thickness of said walls and the lack ofan interior cushioning filling within the hollow ulb.

Now an object of this invention is to avoid the above defects byproviding-a sealing strip of soft sponge rubber material enclosed withina protective outer casing having relatively very thin continuous wallsof soft rubber or rubber-like material. Such thin outer casing willprevent the spongy material from absorbing moisture and from a tendencyto stick to the door or door jamb surfaces against which it iscompressed in use. Since the outer casing is surface bonded to theinterior spongy material it may be relatively very thin and flexible andstill have sufficient strength to withstand all ordinary wear and tearthereupon in use.

Another object of this invention is to provide an efficient andeconomical method of making such a sealing strip by first extruding thethin wall outer casing and progressively filling said casing withungelled foamed latex material immediately after said casing is formedto prevent partial collapse or other distortion thereof due to itsthinness and consequent lack of strength.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawing:

Fig. 1 is a cross section of one form of the strip of this invention,but shows the thickness of walls of the outer casing exaggerated forsake of greater clearness.

Fig. 2 is a diagrammatic view illustrating how the methd of thisinvention may be carried out.

The strip shown in Fig. 1 comprises a main body 19 of vulcanized foamedrubber latex material which has a r 2,774,120 Patented Dec. 18, 1956soft and flexible cellular structure which is very freely compressible.This main body 10 is fully encased by and surface bonded to a thinexterior skin or casing 11 of soft rubber or similar rubber-likematerial. This casing 11 need have only such wall thickness as willprovide a water-proofing skin on the main body 10 of the strip. Due tothe fact that casing 11 is surface bonded throughout its entire surfaceto the spongy main body 10 and is supported thereby it is necessary thatsaid casing 11 have only from one-half to one-third of the wallthickness ordinarily used in similar sealing strips having hollow bulbs.Thus economy in weight of material is obtained.

A continuous longitudinal attaching flange 12 is formed integral withcasing 11 and of the same material therewith, but the thickness of saidflange 12 may be made as great as desired for strength purposesregardless of the thinness of casing 11. The flexible flange 12 isjoined to casing 11 by the continuous flexible neck 13 and serves as themeans for attaching the strip to a door frame member or door jamb bydriving nails or screws through said flange 12, or by any otherattachment means, simply by swinging the main portion of the strip outof the way by hinging same about the flexible neck 13 in an obviousmanner.

According to this invention the thin-wall rubber casing 11 and theintegral flange 12 are formed to the desired cross section by extrudingsame through a correspondingly shaped extrusion aperture, in a wellknown manner. Fig. 2 shows the extrusion head 20 from which the extrudedthin-wall casing 11 and integral flange 12 continuously emerge at aconstant rate. As the tubed casing 11 leaves the extruding aperture itis filled with a suitable ungelled foamed latex compound which is flowedthereinto at a low pressure, preferably no greater pressure than isrequired to cause such filling. The conduit 25 through which the foamedlatex compound enters casing 11 extends through the interior of thepressure chamber 21 behind .the extrusion aperture 22 and thence outthrough the otherwise closed off central portion 23 of the extrusiondie. The freely flowing ungelled foamed latex material 27 is deliveredcentrally of casing 11 by the nozzle 26 within a short distance, say oneinch, of the extrusion aperture 22 so that casing 11 will be filled assoon as is practical after it leaves the extrusion aperture.

Preferably a quick gelling foam latex compound is used so that it willgel within a short distance, say a foot or two, of the tubing head 20and thereafter provide an interior support for the thin-wall casing 11which in its uncured newly extruded condition is Weak and flimsy andhence subject :to collapse or other distortion unless supported by somemeans. In Fig. 2 the heavy cross section lines beginning at point 28indicate the gelled foamed latex compound. Fig. 1 of the drawings may beconsidered as showing a cross section through the uncured strip at lineAA in Fig. 2. Upon gelling the injected foamed latex compound sets andbecomes an adequate interior support for maintaining the sectional shapeof the thin-wall casing 11 until it is finally cured in any suitablemanner.

In the diagrammatic showing in Fig. 2, the extruded and filled strippasses continuously from the extruder head 24} upon a belt conveyor 40which is suitably driven at the same rate of travel as that of theemerging strip. Conveyor 49 supports and conveys the strip through avulcanizing chamber 45 maintained at the proper temperature toprogressively and continuously cure the strip as it passes through saidchamber 45. During such curing the thin-wall rubber casing 11 and thefoamed latex filler material are cured simultaneously and surface bondedto one another and thereafter form a strong integral structure. Thefinal cured strip is very soft and yieldable under compression due toits soft spongy main body 10, while the thin-wall casing 11 prevents itfrom acting as a sponge to absorb water and serves as a protective skinthereon for withstanding surface Wear or rough,

usage.

While the embodiment of the'present invention as here stood that other"forms might be adopted.

What iscIaimed is as follows: w

1, A rubber-like cus hioning sealing strip Comprising; a preformedseamless relatively thin Walled outer hollow casing of rubber-likematerial, and a foam latex rubber core completely'filling said hollowcasing, said core being in disclosed, constitntes'a preferred form,- itis to be'undercompletely encased, formed and shaped in situ' in saidcasing for-providing a support for said casing and having contactingsurface portions bonded thereto. 7 V

2. VA rubberflike cushioning sealing strip comprising;

a'preforrned seamless relatively thin Walled outer-casing of rubber-likematerial having a portion integrally formed therewith for forming amounting flange for said casing and a foam latex rubber core completelycontained Within said casing and shaped, formed'and bonded in situ insaid casing and providing a supporttherefore. v

3. A composite rubber-like cushioning sealing strip comprising; apreformed seamless outer thin Walled hollow casing of rubber-likematerial having a flat base like portiom'aasolid flange portion ofrelatively thicker mate-' rial than said casing integrally formed and'hiiigedly' attached to and substantially parallel with'thefiat portionof said casing for holding said strip on a: support 'andia foam latexrubber core completely filling said hollow a casing, said core beingcompletely enclosed, and formed and'shaped in situ therein and havingvcontacting surface portions bonded thereto for providing a 'sup'port'forthe V v thin Walled casing portion of the strip. V

